i have another question that i forgot to add. is it okay to begin hardening the plants off once they germinate. for instance, instead of exposing them to grow lights after sprouting, can i just begin exposing them to outdoor light?

Soil or potting mix.

I start with Miracle Grow Seed Starting Potting Mix.
Next I use Miracle Grow Potting Soil.

I find it beneficial to screen both of the above to remove large particles of wood, etc. I use a piece of "rat wire", framed.

John

Link below is to a recent discussion on suggested potting mixes. Search "potting mix" for even more discussions.

hardening the plants off once they germinate

They are very tender at this stage. Direct sun will kill them. Filtered sun through a window will work but lights are best as you can get them just 1" above the seedlings and so prevent them getting leggy.

Check out the FAQ here (link top of the front page) for the "How to grow tomatoes from seed" FAQ.

Dave

Here is a link that might be useful: Potting mixes for seedlings

how many days should i leave them in a window? and how many days do you guys let your seedlings sit under grow lights?

~~~ how many days do you guys let your seedlings sit under grow lights? ~~~

Until they can go outside with an acceptably small risk of damage from temps, sun, wind, storms etc.

dave, how do you tell when its time though?

Tomato seedlings are usually 6-8" tall, have central stem at least 1/4" in diameter, and have at least 2 sets of true leaves or preferably 3 sets before they are transplanted to the garden. But even then transplant time depends on the weather in your area and the soil temps.

I would think that in zone 9 it's past plant out time so now you just have to get them to transplant size. Most of us start our seeds 6-8 weeks before our plant out date and they are kept inside under lights until just a few days before that date when we begin hardening them off.

Dave (the other one)

Bate181,

How old and at what stage are your plants?

When you say shallow, small cells ... What size? One sprout or several each?

How many sprouts do you have and how many plants do you want to end up with?

If you have many but only want a few you can take more risk and run some experiments for yourself.

Sixpack containers are great for first stage transplants. Single serving yogurt cups anything like that with a couple small holes in the bottom or low on the side. I prefer the bottom because I bottom water only. If you are in zone 9, you won't need to do more thn one transplanting prior to setting out.

I believe that filtered sun, protection from much more than a breeze and temps between 50-75F for and hour or so anytime you can give it to them is good even before true leaf stage. Increasing a hr. or so every few days as weather permits but they are somewhat fragile and as Dave mentions it is easy to fry them from sun or wind.

Have Fun!

dave, I planted new seeds 3 days ago. many of them are starting to emerge.

I planted them in egg cartons. most cells have 2 seeds. some have 1. i planted about 30-35 seeds total. i intend on growing 10-15 plants.

im kinda confused about hardening off and whether to use grow lights or not because most people dont start seeds right now and the normal seed starting protocol is probably different starting seeds now than during winter.

im wondering if i even need to set them under grow lights once they all germinate because i have outside temps of 75-80 for the next ten days, with overnight lows of ~55.

im in southern california, so i have a larger growing window and thats why these intend to be a fall harvest

If you can give them a sunny window and or protected space outside I'd think you'd be fine but I've never had the conditions you descirbe.

Without the lights, they may tend to get leggy and may require another deeper transplanting, more support earlier etc.

In sometime less than 2 weeks hopefully you'll be splitting them up into individual containers as singles and can experiment on one set.

Best of luck!